Department of BioNano Technology, Gachon University, 1342 Seongnamdae-ro, Sujeong-gu, Seongnam-Si, Gyeonggi-do 13120, Korea.
Korea Railroad Research Institute (KRRI), 176 Cheoldobakmulkwan-ro, Uiwang-si, Gyeonggi-do 16105, Korea.
Sensors (Basel). 2018 Feb 3;18(2):457. doi: 10.3390/s18020457.
In this study, we describe a novel peroxidase-like activity of Co-aminoclay [CoAC] present at pH ~5.0 and its application to fluorescent biosensor for the determination of H₂O₂ and glucose. It is synthesized with aminoclays (ACs) entrapping cationic metals such as Fe, Cu, Al, Co., Ce, Ni, Mn, and Zn to find enzyme mimicking ACs by sol-gel ambient conditions. Through the screening of catalytic activities by the typical colorimetric reaction employing 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid)diammonium salt (ABTS) as a substrate with or without H₂O₂, Fe, Cu, and CoACs are found to exhibit peroxidase-like activity, as well as oxidase-like activity was observed from Ce and MnACs. Among them, CoAC shows exceptionally high peroxidase-like activity, presumably due to its ability to induce electron transfer between substrates and H₂O₂. CoAC is then used to catalyze the oxidation of Amplex UltraRed (AUR) into a fluorescent end product, which enables a sensitive fluorescent detection of H₂O₂. Moreover, a highly sensitive and selective glucose biosensing strategy is developed, based on enzyme cascade reaction between glucose oxidase (GOx) and CoAC. Using this strategy, a highly linear fluorescence enhancement is verified when the concentration of glucose is increased in a wide range from 10 μM to 1 mM with a lower detection limit of 5 μM. The practical diagnostic capability of the assay system is also verified by its use to detect glucose in human blood serum. Based on these results, it is anticipated that CoAC can serve as potent peroxidase mimetics for the detection of clinically important target molecules.
在本研究中，我们描述了一种新型过氧化物酶样活性的 Co-aminoclay [CoAC]，其在 pH~5.0 时存在，并将其应用于荧光生物传感器中，用于测定 H₂O₂和葡萄糖。它是通过在溶胶-凝胶环境条件下，用氨基粘土（ACs）包封阳离子金属（如 Fe、Cu、Al、Co、Ce、Ni、Mn 和 Zn）来合成的，以寻找具有酶模拟活性的 ACs。通过采用 2,2'-联氮双（3-乙基苯并噻唑啉-6-磺酸）二铵盐（ABTS）作为底物的典型比色反应筛选催化活性，发现 Fe、Cu 和 CoACs 具有过氧化物酶样活性，而 Ce 和 MnACs 则表现出氧化酶样活性。其中，CoAC 表现出异常高的过氧化物酶样活性，这可能归因于其能够在底物和 H₂O₂之间诱导电子转移。然后 CoAC 用于催化 Amplex UltraRed（AUR）氧化成荧光终产物，从而能够对 H₂O₂进行灵敏的荧光检测。此外，基于葡萄糖氧化酶（GOx）和 CoAC 之间的酶级联反应，开发了一种高灵敏度和选择性的葡萄糖生物传感策略。使用该策略，当葡萄糖浓度在 10 μM 至 1 mM 的宽范围内增加时，验证了高度线性的荧光增强，检测限低至 5 μM。还通过使用该方法检测人血清中的葡萄糖来验证该测定系统的实际诊断能力。基于这些结果，预计 CoAC 可作为用于检测临床重要靶分子的有效过氧化物酶模拟物。
